Glutamine
Glutamine is a conditionally essential amino acid studied for gut, immune, and recovery outcomes. Benefits are context-specific.
Overview
What is glutamine?
Glutamine is one of the 20 amino acids that make up proteins.
Conditionally essential, glutamine is utilised in greater amounts during periods of illness and trauma.
There is limited evidence that glutamine enhances muscle growth or reduces body fat.
Whilst glutamine is marketed as an ergogenic aid that can improve athletic performance and recovery there is limited high quality evidence for this purpose.
There is reliable evidence that glutamine can improve recovery in burn victims or in cases of severe physical stress and illness.
Dosage
A typical dose of glutamine is at least 5 grams per day, but higher doses of up to 30 grams per day have been safely used in studies.
For immunity and intestinal function, studies use glutamine at a dose of 0.25-0.90 g/kg/day. Doses approaching the higher end of this range may increase plasma ammonia.
For athletic performance, studies use glutamine at a dose of 0.07-0.90 g/kg/day. Doses approaching the higher end of this range may increase plasma ammonia.
Effect graph
Effect heatmap
SupplementDEX Database
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Database Snapshot
Most glutamine research is concentrated in a handful of conditions.
- Athletic performance accounts for 7 of 18 studies (39%).
- Immunity accounts for 5 of 18 studies (28%).
- Crohn's disease accounts for 3 of 18 studies (17%).
Dietary Sources
Top dietary sources
Ranked by amount per 100 g
Glutamine intake from the diet is roughly 3-6 grams per day assuming a protein intake of 0.8 to 1.6 g/kg/day.
Safety
Glutamine is generally well tolerated. Doses of up to 30 grams per day have been taken for up to 14 days without side effects in healthy young adults.
Dose windows
Short-term
Glutamine has been used at a dose of 0.9 g/kg/day for up to 6 weeks.
Long-term
Glutamine supplementation at a dose of less than 0.65 g/kg/day is likely safe. The optimal long-term glutamine dosage is not known. Most studies examine acute glutamine dosage.
Special populations
Pregnancy & breastfeeding
Limited evidenceIn pregnant and lactating women, glutamine is likely safe when consumed from dietary sources. There is insufficient evidence for the effects of glutamine supplementation in pregnant and lactating women.
Children
Likely safeIn children, glutamine is likely safe. Doses of up to 0.65 g/kg per day have been well-tolerated in pediatric oncology patients.
Other notes
Acute doses of up to 30 grams are likely safe. The lowest dose shown to increase serum ammonia is 0.75 g/kg. Doses of 0.65 g/kg per day are well tolerated and do not alter plasma ammonia levels. Studies typically use a dose of 0.25 to 0.9 g/kg/day.
Frequently Asked Questions
Takeaway
Glutamine is an amino acid that is found in a wide range of animal meats, eggs, and tofu.
Glutamine may confer benefits for immunity during prolonged exercise by helping to maintain the integrity of the intestinal barrier. During times of extreme physiological stress, glutamine may help support wound healing.
There is no evidence that glutamine can reliably increase muscle growth or improve body composition.
References
Sources18 references
SupplementDEX uses only high-quality sources to determine supplement effectiveness.
SupplementDEX Database · Athletic performance
7 references1.SupplementDEX Database: Athletic performance — The effect of glutamine supplementation on athletic performance, body composition, and immune function: A systematic review and a meta-analysis of clinical trials2019
A meta-analysis of RCTs found glutamine supplementation did not significantly improve athletic performance, body composition, or VO2 max versus placebo.
2.SupplementDEX Database: Athletic performance — Glutamine and carbohydrate supplements reduce ammonemia increase during endurance field exercise2007
In a crossover study of 15 runners, glutamine plus carbohydrate before endurance exercise reduced exercise-induced hyperammonemia versus placebo or glutamine alone.
3.SupplementDEX Database: Athletic performance — Effect of glutamine supplementation combined with resistance training in young adults2001
In a 6-week RCT of 31 young adults doing resistance training, glutamine 0.9 g/kg lean mass/day did not increase strength or lean mass gains versus placebo.
4.SupplementDEX Database: Athletic performance — Acute L-glutamine ingestion does not improve maximal effort exercise1998
In a crossover trial of 10 trained men, acute glutamine ingestion did not improve maximal cycling performance or alter acid-base balance versus placebo.
5.SupplementDEX Database: Athletic performance — Competitive sustained exercise in humans, lymphokine activated killer cell activity, and glutamine--an intervention study1998
In an RCT of 16 marathon runners, post-race glutamine 100 mg/kg preserved plasma glutamine but did not prevent exercise-induced lymphocyte function changes versus placebo.
6.SupplementDEX Database: Athletic performance — Effect of glutamine supplementation on changes in the immune system induced by repeated exercise1998
In a crossover RCT of athletes, glutamine supplementation did not prevent exercise-induced declines in lymphocyte proliferation or LAK cell activity versus placebo.
7.SupplementDEX Database: Athletic performance — The effects of oral glutamine supplementation on athletes after prolonged, exhaustive exercise1997
In controlled trials of athletes and sedentary controls, oral glutamine after exhaustive exercise restored plasma glutamine but did not clearly prevent immunosuppression.
SupplementDEX Database · Crohn's disease
3 references8.SupplementDEX Database: Crohn's disease — Glutamine and whey protein improve intestinal permeability and morphology in patients with Crohn's disease: a randomized controlled trial2012
In a 2-month RCT of 15 Crohn disease patients in remission, oral glutamine 0.5 g/kg/day did not improve intestinal permeability or morphology versus whey protein control.
9.SupplementDEX Database: Crohn's disease — Double-blind randomized controlled trial of glutamine-enriched polymeric diet in the treatment of active Crohn's disease2000
In a 6-week double-blind RCT, a glutamine-enriched polymeric diet did not improve Crohn disease activity scores versus standard polymeric diet.
10.SupplementDEX Database: Crohn's disease — Effect of long-term oral glutamine supplements on small intestinal permeability in patients with Crohn's disease1999
In a 4-week RCT of 7 Crohn disease patients with increased intestinal permeability, oral glutamine 21 g/day did not normalize permeability versus control diet.
11.SupplementDEX Database: Duchenne muscular dystrophy — Lack of functional benefit with glutamine versus placebo in Duchenne muscular dystrophy: a randomized crossover trial2009
In a 4-month crossover RCT of 30 ambulant Duchenne muscular dystrophy boys, glutamine 0.5 g/kg/day did not improve walking speed or muscle function versus placebo.
12.SupplementDEX Database: Duchenne muscular dystrophy — Oral glutamine and amino acid supplementation inhibit whole-body protein degradation in children with Duchenne muscular dystrophy2006
In a 10-day RCT of 26 boys with Duchenne muscular dystrophy, oral glutamine 0.5 g/kg/day reduced whole-body protein degradation more than an isonitrogenous amino acid mixture.
13.SupplementDEX Database: Duchenne muscular dystrophy — CINRG randomized controlled trial of creatine and glutamine in Duchenne muscular dystrophy2005
In a 6-month RCT of 50 ambulant Duchenne boys, creatine plus glutamine did not significantly improve muscle strength versus placebo, though a subgroup showed possible benefit.
SupplementDEX Database · Immunity
5 references14.SupplementDEX Database: Immunity — Glutamine supplementation reduces markers of intestinal permeability during running in the heat in a dose-dependent manner2017
In crossover trials of 10 runners in heat, acute glutamine 0.5–0.9 g/kg reduced intestinal permeability markers during exercise versus placebo.
15.SupplementDEX Database: Immunity — The effects of acute oral glutamine supplementation on exercise-induced gastrointestinal permeability and heat shock protein expression in peripheral blood mononuclear cells2015
In 7 active adults, a single pre-exercise glutamine dose did not significantly reduce exercise-induced gastrointestinal permeability versus control.
16.SupplementDEX Database: Immunity — Effect of glutamine supplementation on exercise-induced changes in lymphocyte function2001
In a crossover study of 10 athletes, glutamine supplementation during 2 h exercise did not prevent exercise-induced lymphocyte subset changes versus placebo.
17.SupplementDEX Database: Immunity — Effect of oral glutamine supplementation on human neutrophil lipopolysaccharide-stimulated degranulation following prolonged exercise2000
In a crossover trial of 7 trained men after 2 h cycling, glutamine did not improve post-exercise neutrophil oxidative burst activity versus placebo.
18.SupplementDEX Database: Immunity — Does glutamine have a role in reducing infections in athletes?1996
In a study of 151 athletes and 755 controls, lower post-exercise plasma glutamine was associated with more upper respiratory infections, but supplementation effects were inconclusive.